Contact Us

Grantee Research Project Results

Final Report: Recycling of Greenhouse Gases to Fuels & Chemicals

EPA Contract Number: EPD11046
Title: Recycling of Greenhouse Gases to Fuels & Chemicals
Investigators: Molter, Trent
Small Business: Sustainable Innovations LLC
EPA Contact: Richards, April
Phase: I
Project Period: March 1, 2011 through August 31, 2011
Project Amount: $79,980
RFA: Small Business Innovation Research (SBIR) - Phase I (2011) RFA Text |  Recipients Lists
Research Category: Small Business Innovation Research (SBIR) , SBIR - Greenhouse Gases

Description:

Currently, atmospheric pollutants, including carbon dioxide (CO2), nitrogen oxides (NOx) and sulfur oxides (SOx), are emitted into the atmosphere at unprecedented rates. Some of these pollutants have been linked to global warming. Capture and sequestration of carbon dioxide (CO2), nitrogen oxides (NOx) and sulfur oxides (SOx) is costly and may have unforeseen long-term environmental consequences. The ability to recycle atmospheric pollutants by electrochemical conversion into useful commodity chemicals, such as methanol (CH3OH), ammonia (NH3) and sulfuric acid (H2SO4), would be highly beneficial to the environment and could engender positive economics. Sustainable Innovations is developing an Electrochemical Greenhouse Gas Recycling System (EGGRS) that recycles greenhouse gases into saleable and valuable commodity chemicals. This EGGRS system is based on an electrochemical reduction process and, when coupled to renewables, the EGGRS is a carbon negative technology.
 
The overall concept for an innovative EGGRS system is shown in Figure 1. The explanation of the system henceforth focuses on CO2 recycling. In this system, either nascent air or exhaust from factory or power plant effluent is fed to a CO2 absorber subsystem. In this subsystem, CO2 is absorbed into an absorbent medium via a chemical or physical process that allows clean air to pass through. This fluid then is passed into a stripper system wherein the CO2 is removed from the medium—ideally in a concentrated form—and sent to an electrochemical cell.
 
Figure 1
 
Figure 1: Overall EGGRS System Concept
 
An alternative embodiment uses gas streams with high CO2 content, such as those derived from combustion-based processes, which can be passed directly into the electrochemical cell after compression. In this regard, a mixed stream of CO2 and air populates the cathode chamber of the cell at pressure. The CO2 reacts to form hydrocarbons. This configuration eliminates the need for an absorber/stripper subsystem.
 
Although initial technology development has focused on CO2 conversion, converting other pollutants such as NOx and SOx to usable commodities is possible. Overall, the primary environmental benefit of the EGGRS system is in the prevention of greenhouse gas (GHG) emissions via conversion of GHG and atmospheric pollutants into useable commodity chemicals.

Summary/Accomplishments (Outputs/Outcomes):

 

Work Tasks

 

Results

Task 1: Conversion of SOx and NOx to Useable Commodities

Modest increase in reaction temperature is beneficial to the production of hydrocarbon products. Controlling the ratio of reactants H2:CO2 affects the concentration of hydrocarbon products.

Task 2: Single Cell Hardware Fabrication

A dramatic increase in current density occurred the flow field of the baseline CO2 reduction stack was modified. The reaction rate was an order of magnitude faster. It is noteworthy that this stack was hydraulically tested, and exhibited no problems when its cathode was pressurized to 3,000 psi; therefore there was no obvious negative consequence of this modification in terms of the loss of the necessary structural integrity.

Task 3: Testing and Analytical Analysis

The gaseous exhaust of the CO2 reduction system was connected to the anode of a hydrogen detector cell. This cell was held at a constant voltage with a DC power supply which the electrical current drawn by the cell was monitored. The hydrogen in the stream was pumped across the membrane and was quantified by the current drawn by the cell. This allowed us to evaluate how much of the current in the EGGRS cell was used for CO2 reduction versus hydrogen generation.

Task 4: System Design Modifications – Advanced EGGRS Cell Design

Two major modifications were made to the system used to support EGGRS testing. Ports were added so that a precise volume of liquid could be added to the cathode of the cell. This modification allowed us to better quantify the products generated by the system. The second major modification was the addition of a gas manifold that allowed control of the flow rates of multiple low pressure gases. System tests showed 100% conversion of the cell current to hydrocarbon byproducts under nominal cell operating conditions.

Task 5: Top Level Design & LCA For Large Scale EGGRS System

The EGGRS will produce a range of commodity chemicals via the consumption of CO2 . The coupling of a CO2 emitter (conventional power generation plant) with an EGGRS and a low carbon footprint is feasible up to a giga watt scale. A 105 MW sized EGGRS will consume upwards of 1 million tonnes of CO2 over its lifetime (15 years).

Task 6: Techno-Economic Study of The EGGRS Technology

Upon completion of our techno-economic study we concluded that the EGGRS technology has a significant market position with respect to production of acetic acid and methanol. The Sankey and P&ID diagrams from Task 5 were incorporated into the techno-economic model.

Conclusions:

  1. For nearly all hydrocarbon product scenarios from the EGGRS, the economics of the process appear to be favorable.
  2. When powered by renewable or nuclear energy sources, the EGGRS consumes more CO2 in a small fraction of a year than the CO2 emitted when building the EGGRS.
  3. Application scenarios and EGGRS' size significantly affect system economics.
  4. Hydrocarbon product global demands must be considered, as well as “unit value” of hydrocarbon product. In some cases, a single large EGGRS installation could meet the entire global demand of a particular hydrocarbon product (e.g., oxalic acid).
  5. The value of “carbon offsets” realized by the EGGRS is very low when compared to the value of product hydrocarbon and product oxygen.
  6. Even when powered by fossil fuel generated electricity, the EGGRS still can provide a lower cost method of producing most of the target hydrocarbons (than when produced in the traditional though in this case it would not be a carbon neutral process.
  7. Simpler hydrocarbon products result in much higher CO2 consumption.

Commercialization

Sustainable Innovations’ EGGRS system represents a viable commercial choice for recycling atmospheric pollutants into commodity chemicals. There has been real interest from stakeholders in:

  1. Atmospheric scrubbing of greenhouse gases.
  2. Recycling of greenhouse gases from large-scale emitters, including coal-fired power plants.
  3. Generation of fuels and commodity chemicals at small- to moderate-use sites.

The chemicals produced appear to be cost competitive with current commodity prices and have enormous market potential. The methanol market is, for example, growing and could provide annual revenues well in excess of $100 million after 5 years of sales.

Top of Page

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.

Site Navigation

Related Information